Fuel pump



' Aug. 10, 1948.

Filed May 18, 1945 J. 1.. A. MOULET 2,446,604

rum. ruur s Sheets- Sheet 1 I NVENTOR AT- is.

Aug. 10, 1948. .J. L. 1.. A. A. MOULET 2,446,604

FUEL PUMP Filed May 18, 1945 a Sheets-Sheet 2 Aug. w, 1948.

J. L. L. A. A. MOULET 2,446,604

FUEL PUMP Filed May 18, 1945 :s Sheets-Sheet :s

a 29 2e INVE NT R.

Patented Aug. 10, 1948 OFFICE FUEL PUMP Jean Louis Leon Alexandre Albert Moulet,

Oullin s, France Application May 18, 1945, Serial No. 594,483 In France June 27, 1942 Section 1, Public Law 690, August 8, 1946 Patent explres June 2.7, 1963 My invention has for its object a pump adapted to transmit substantially equal pressures to different liquids, one of which is a lubricant and the other may be a liquid fuel intended for the feeding of an internal combustion motor. According to a primary feature of said invention, this pump is constituted by one or more cylinders inside each-of which may slide two pistons arranged in series and secured to one another with a certain longitudinal play; the first piston acts on'the lubricant which transmits its pressure to the second piston which acts in its turn on the fuel; the arrangement forms thus two elementary pumps, one for the fuel and one for the lubricant which ensures thus a permanent lubrication of the pump and its auxiliary mechanisms at a pressure which is in constant equilibrium with that of the fuel.

According to a further feature of the invention, the pressure chamber of the fuel pump is provided with a by-pass including a freely sliding piston adapted to set the inlet in direct com munication with the outlet, said freely sliding piston remaining in equilibrium between the pressure of the fuel on one side thereof and that of the lubricant acting on the other side under the influence of a suitable regulator.

In the case of a multicylinder pump, the different cylinders may be arranged in parallelism round the control shaft, the pistons being simultaneously actuated as well known in the art by means of a plate arranged obliquely with ref erence to said control shaft and the rotation of which produces the reciprocation of the pistons.

cordance with the desired cycle through suitable mechanical, hydraulic, electric or the like control means while the lubricant is forced directly into the common injector lubricating pipe.

I have described hereinafter an embodiment of my invention, given by way of example, and 11- v with a fuel distributor for the motor cylinders.

Fig. 2 is a horizonal cross-section through line 11-11 of Fig. 1.

Fig. 3 is a horizontal cross-section through line III-III of Fig. 1.

Fig. 4 is a horizontal cross-section through line IV-IV of Fig. 1. 4

distributor for which it provides both lubrication and equilibrium in operation, as well as for the other parts of .the equipment, perfect fluid tightness as-concerns the fuel being simultaneously ensured by means of a, slight overpressure of lubricant.

When feeding an internal combustion motor and more particularly a motor of the gasoline explosion type, the pump may be used without a fuel distributor, said fuel being in such a. case fed directly to the injectors under permanent pressure and the distribution being effected in ac- Fig. 5 is 'a cross-section of part of the pump through line V-V of Fig. 4. I

Fig. 6 is a cross-section of another part of the pump through line VI--VI of Fig. 4.

Fig. 7 is a detail cross-sectional view through line VII-VII of Fig. l. I

Referring to said drawings showing by way of example a pump including five parallel cylinders, it is apparent that said pump is constituted by the assembly of three casings to wit: a casing l containing the control mechanisms, a casing 2 containing the elementary pumps and'the casing 3 containing the fuel distributor.

These casings are connected .through their flanges such as 4 and 5 rigidly secured to the adjacent'casing by means of annuiarly distributed bolts. studs or the like.

The casing l is provided with a flange t for mounting the pump assembly on the motor. The pump is driven through the' shaft l rotatably carried in the bush 8. Said shaft I is provided with an oblique bearing 9 whichvcarries a loose gearwheel I'l' through the agency of-a needle hearing or the like part. This gearwheel l iis'providedwith toothed sectors in constant engagement with r the teeth of another gearwheel I! which is 'stationary and-rigid with the casing I.

The gearwheel H cannot rotate, but the bent shaft 1 as it rotates causes it to assume a tacking motion through the agency of the bearing l3.

This motion is transmitted simultaneously to each of ,the five pistons ll adapted .to slide in the corresponding cylinders l5 arranged in parallelism with the axis of the pump and distributed at equal intervals round same. These pistons are thus urged into a reciprocating motion due to the fact that the extensions 16 of the gearwheel ll act on the connecting rods 11 of the pistons cylinder II. The two pistons ll and ii are assembled with some play and between them isprovided achamberilthevolumeofwhichtherecollecting chamber or with the suction collecting chamber ll through a duct 53 may communicate by-pass system including a piston 55 adapted to move freely in either direction inside a cylinder 58 under the action respectively of the fuel Pressure in the collecting chamber 53 and of the oil pressure in the chamber II. The freely moving piston 5| covers and uncovers during its displacefore vary and which constitutes an elementary oil pump.

The entrance of oil intothepumpll iseil'ected through a port II (Fig. 6) provided in the flange of the pump in front of a port provided in the casing of the motor and fed with oil under pressure by the lubricating circuit of the motor. This oil enters the chamber closed by a plug and passes through aillter 2! inside the general casing of the pump after lifting aball valve ll which serves to prevent the pump from becoming empty when it ceases nmning.

Theoilentersthenagroove aensuresthelubrication of thebush I and passes into the central channelllboredalongtheaxlsofthepump shaft I. Tothe endofthisshaftissecuredby meansof a key it and ahollow screw 32, asleeve ll centrally fitted lnsidethebush ll integral with or rigidly secured to the stationary gearwheel l2. Thereactlon producedintheshaftlbythemotionofthegearwheel ll isabsorbedbytheball thrust bearing II. The sleeve 33 rotating with the shaft drives through a screwdriver connection It the oil feed distributor II. Said distributor rotates inside a bearing 3! rigid with the casing I and provided axially with an oil feed channel 3! opening in front of the central channel SI of the pumpshaft I. The oil passes from said alined channels SI and ll into the channel ll leading to the abovementioned chamber 24 of the elementary oil pump. The oil distributor comprises moreover at its outer periphery, a, narrow anmilar chamber II the lowerpart In of which extends onlyoverpartofacircumferenceasshownin cross-section in Fig. '7.

It is apparent that, as it rotates, the distributor causes the channels 4. of the different cylinders to communicate in turn, first with the oil feed channel 3! and then with the part annular chamber portion a. Through the associated movements of the pistons and of the distributor, the oil is sucked through the channels 3| and 39 into the different pistons in succession, out of which they are forced into the circular chamber II. From this chamber. the oil under pressure is led through the channel 42 into the fuel distributor ll of which it ensures the lubrication and moreover, through the channel 44, towards the regulator of which it controls the operation, as will be disclosed hereinafter.

Furthermore, as the pistons II are provided with a reciprocating motion, there is a consequent variation in volume of the chambers 45 which form the elementary fuel pumps. The fuel enters said pumps under acertain pressure through the connection 46 (Fig. 3), the filters 41-" and the annular chamber 49 in which the fuel is collected for suction into the chambers 45.. It enters the latter through the groove I and the ports Illinoovered only when the piston It is at the end of its suction stroke. Durin the return stroke, the

fuel is forced through the flap valve 52 into the annular chamber 53 forming the delivery collecting chamber and from said space into the filter I and the fuel distributor Q3. The delivery ments a suitably shaped port SI which allows the temporary return flow of part of the fuel which is delivered back into the suction collecting chamber IS. The oil pressure in the chamber 51 and consequently that of the fuel in the collecting chamber 53 is determined by the equilibrium of the slide valve 59 subjected on one side to the oil pressure in the channel ll and on the other to the action of a. set of levers "-1! adapted to transmit the variable force exerted by the pressure e ator.

The slide valve 5!, as it moves, uncovers either the oil inlet ports 62 or the oil escape ports I inside the casin I whereby it adjusts the oil pressure in the chamber 51 through the channel I.

A calibrated diaphragm 65 prevents any jerks from occurring in the transmission of said pressure to the freely sliding piston 55.

The pressure regulator (Figs. 1 and 4) comprises chiefly a yielding diaphragm 66 held tightly between two flanges 61 and G8 inside a recess provided between a wall of the casing I and a cover it secured to said main casing throughan annular series of bolts or studs.

The large diameter diaphragm 66 separates the recess into two chambers II and 'II which may communicate through the connections I! and I3 (Fig. 4) with two dliferent sources of pressure.

If one uses only one source of pressure connected I for instance with the chamber 1., the chamber ii is subjected to the circumambient pressure through a port provided in the wall of the casing.

The diaphragm 66 is moreover subiected to the action of a spring ll adjustable from the outside through the screw IS and a sliding not It acting on said spring.

The diaphragm it acts through a central boss TI on the lever 6| (Fig. l) with the interposition of a ball 18. v

A small yielding diaphragm I! is arranged so as to separate the chamber II from the inside of the casing i without preventing the central boss 11 from acting on the ball 18.

The crank lever 61 (Fig. 1) rotates round its axis and transmits to the lever 60 the prmsure it receives from the ball 18 with the interposition of the ball 80 located inside the cage ll forming Part of the lever 82 (Fig. 4) pivotaliy secured to the spindle 83. This lever 32 may b moved from outside the casing by means of a micrometric screw l4 including an inner set screw for bolding the lever 82 in the desired position by fastening the cover 86.

The pump which has been described by way of example is particularly adapted to provide the feeding of a motor through direct atomising of the fuel into the cylinders and it is associated with means for distributing the fuel towards the different cylinders of the motor.

These distributing means are contained in the.

as 99 the number of the cylinders and which may be arranged for in-v stance in two rows. Openings 90 and 9I are provided in the rotor for communication with the connections 92-93 from which the pipes leading to the cylinders start. The size and direction of these openings are such as'will provide for the feedin of each cylinder at the moment and during the time required by the distribution used for the motor.

The rotor 81 rotates inside the bearing 94. Lubricating grooves 95 and 96 are provided-between the rows or tiers of connections 89 and are fed with oil under pressure through the channel 91 communicating with the delivery ofthe oil pumps through the chamber 99.

As the inside of the pump casing should be at circumambient pressure, a channel 99 (Fig. 1) is provided in the flange 0, for removing the excess oil towards the casing of the motor.

it is upside down with the flange 6 uppermost, the channel 99 can no longer fulfil this part and there may be provided a pump for exhausting the oil, as is shown in Fig. 5. This pump includes a cylinder I00 containing a piston IOI the suction stroke of which is ensured by a spring I02. and

the delivery stroke by a push member I03 con-- said mounting being constituted by a step I08 urged by a spring I09 against a stop formed by an annulus H0. 'Of course the spring I09 is strong enough to constantly make the step bear against its stop during normal operation and it is compressed only when the friction between tht piston IN and its cylinder I00 becomes exaggerated.

The working of the pump arrangement described is'as follows: As it rotates, the shaft I gives the movable gearwheel II a tacking motion which communicates a reciprocating motion to all the pairs of cooperating pistons 'I4--2I, which pistons are connected so as to provide between them a variable volume chamber 24. The oil distributor 3,7 is keyed to the shaft 1 in a manner such that the channel 39 comes opposite the channel 40 at the moment when the piston It begins its downward stroke. As the oil is forced under pressure from the motor through the channels 25, 29, 30 and 40, it fills immediately the chambers 24 between the cooperating pistons.

During the same time, the piston 2I produces which is equal to that of 4 For certain positions of the pump, in particular when Iii) in the chamber a depression which becomes apparent at the end of the suction stroke in the groove 50, whereby the fuel is sucked in from the chamber 49 and the fuel container through the connection 40. I

Thus the pistons I4 and 2I execute simultaneously their suction stroke.

During the next or deliverystroke, the piston 2|. forces the fuel out of the chamber 45 which raises the flap valve 52 in the chamber 53 for a predetermined pressure P. The fuel is then led through the pipe 80 towards the distributor and thence through the ports-90 and 9| into the connections 89 communicating through suitable pipes with the motor cylinder.

The Ports 90 and 9| of the distributor are arranged and the distributor Is set with reference to the shaft] in a manner such that the admission of fuel'is effected in each cylinder with the timing and for the duration required by the distribution in the motor.

While the pistons I4 and 2I execute their delivery stroke. the oil in the chamber 24 is automatically set under the pressure of the fuel in the chamber 40, which pressure may be designated by P+1t P being-the pressure of delivery into the collecting chamber 59 and p the loss of head produced by the flap valve 02 in accordance with the compression of the return springof this flap valve. The loss of head which may be ascribed to the movement of the piston 2I may be considered as negligible.' The oil forms thus in the chamber a cushion opposing the leaks of fuel while at the same time ensuring the lubrication of the piston 2|.

At the same time the oil is forced through the channels 42, 90 and 91 into the fuel distributor which is thus subjected on one side to the pressure of the fuel arriving. insidethe rotor under a pressure P and on the other to the pressure P+p .of the'oil entering the chamber 90. These two pressures are very near in value as p may be small. This difference in pressure causes the distributor to bear against the stop in its bearing. I

As to the operation of the regulating means, it

is apparent from Figs. 1 and 4 that if a differential air pressure is exerted between the connections I2 and 13 on either side of the diaphragm 68, the latter will be subjected to a deformation. which through the leverage 60-6I produces a displacement of the slide valve I4 allows a constant adjustable pressure to be added to the action of the air pressure. Moreover it is possible to act through the lever 02 and the screw 04 on the lever arms of the leverage and consequently vary the ratio between the movements of the central boss TI on the diaphragm 66 and those of the slide valve 59. The slide valve 59 receives therefore an upwardly directed impulse of a predetermined adjustable 59. The spring value in direct relationship to the differential air pressure is exerted upwardly, balances the pressure exerted in the downward direction by the oil on the upper surface of the piston, the ports 62 being then covered.

If the differential air pressure modifying the pressure exerted by the regulator is reduced, the slide valve 59 moves furtherdown and begins uncovering the channel 02, which allows acertain amount of oil under pressure to escape and to returnto the pumps. There prevails thus coninFig. is obvious.

. sure acting on the regulator diaphragm.

Now this oil pressure exerts'also in the chamher I! a pressure on the lower end of the freely sliding piston II the other end of which is subiected to the pressure P of the fuel delivered by the pumps. The oil pressure in-the chamber I! is thus equal to the pressure P of the fuel in the chamber '8. The two pressures balance one another and hold the piston I! in a position such that the port I! is partly covered, exactly in accordance with the output required If for any reason whatever, an overpressure arises in-the fuel delivery collecting chamber It, the freely sliding piston Ii moves and uncovers to a greater extent the port I whereby a greater amount of fuel is allowed to return into the suction collecting chamber 8 and the output is reduced.

If. on the contrary, the pressure decreases in the fuel delivery collecting chamber If, the freely sliding piston ll rises under the action of the oil pressure and covers to a greater extent the by-pass port It whereby the output of fuel in- It is apparent that my improved pump allows the simultaneous delivery of a non-lubricant liquid at a predetermined pressure and the lubrication of all moving parts by means of oil held under a pressure at least equal to that of the fuel so as to prevent any leaking of the latter, these cooperating pressures being constantly in equilibrium and held at a' predetermined value by a regulator subjected to a variable or constant outer pressure.

What I claim is:

1. A pump for feeding simultaneously fuel and lubricant to an internal combustion motor comcreases and equilibrium is restoredbetween the two Opposed pressures.-

The chamber l1 and the slide .valve ll form a small auxiliary motor the operation of which is ensured b the excess pressure p of thesoil pressure upstream with reference to the motor. As disclosed hereinabove the excess pressure 1: depends solely on the pressure exerted by the return springs of the flap' valves II.

This excess pressure'p is entirely independent of the operating pressure of the pump. which may be very high. By suitably choosing the value of this pressure p and by reason of the small inertia of the freely sliding piston 85, it is possible to obtain practically. instantaneous regulating movements together with an extremely high sensitivity of the regulator described. I

The working of the oil exhaust pump illustrated The movable gearwheel ii, in its tacking motion, constantly urges the push member I03 into reciprocation so that said member slidesin its hearing I and displaces the piston ill in its cylinder I". .When the oil arrives inside the casing in front of the ports I", it enters the cylinder and at each delivery stroke, is forced through the flap valve it into a pipe communicating with the connection I" and adapted to return it into the motorcasing.

We have described a pump of the barrel type comprising five double cylinders mounted in par allel but obviously any other number of cylinders may be chosen. Onthe other hand, it is apparent the invention,. as defined by the accompanying claims, is far wider and covers in particular multicylinder pumpsthe pistons of which are in alinement orarranged in V or star relationship and through a camshaft or else through any suitable hydraulic, electrical or the like means In this case, the pump is provided with an oil delivery duct and with 'a fuel delivery duct connected respectively with the injector lubricating collecting ".chamber and with the on common injector feeding prising at least one cylinder, two pistons adapted to reciprocate in each cylinder, means for interconnecting the pistons in each cylinder with a longitudinal play between them; means for supplying fuel and lubricant to the cylinders, means for driving the first piston in each cylinder, means whereby said first piston forces the lubricant out of the corresponding cylinder, means whereby said first piston drives the corresponding second piston through the interposed lubricant pressure, means whereby the second piston in each cylinder delivers the fuel into the motor and means whereby the lubricant forced out of each cylinder by the first piston lubricates the pump parts at a pressure which constantly balances that of the fuel. v

2. A pump for feeding simultaneously fuel and lubricant to an internal combustion motor comprising an annular series of parallel cylinders, two alined pistons adapted to reciprocate in each cylinder, means for interconnecting the pistons in each cylinder with a longitudinal play between them, fuel and lubricant supply means, a plate oblique with reference to the axes of the cylinders, means for making saidplate rotate round an axis parallel to the cylinder axes means whereby said plate controls the reciprocation of the first piston in each cylinder, means whereby said first piston forces the lubricant out of the cylinder, means that the description hereinabove must not be c0ns'trued in a limiting sense and that the scope of whereby said first piston drives the corresponding second piston through the interposed lubricant pressure means whereby the second piston in each cylinder delivers the fuel into the motor and means whereby the lubricant forced out of each cylinder by the first piston lubricates the pump parts at a pressurewhich constantly balances that of the fuel.

El. In a pump as claimed in claim 1 the provision of a fuel collecting chamber between the second piston and the means whereby the second piston delivers fuel to the. motor, a by-pass' for said chamber communicating with the fuel supply and with the outletof the collecting chamber and including a freely sliding piston adapted to control the passage through the by-pass between the fuel supply and the outlet of the collecting chamber, means whereby the lubricant pressure acts on the freely sliding piston and a, regulator controlling the pressure of the lubricant.

4. In a, pump as claimed in claim 1 the provision of a fuel collecting chamber between the second fuel supply and the outlet of the collecting chamber, means'whereby the lubricant pressure acts on the freely sliding piston, and .a regulator controlling the pressure of the lubricant including a diaphragm subjected at least-on one side to air pressure, a set of levers operatively related to said diaphragm, a slide valve subjected to the action air pressure acting on the diaphragm.

5. In a pump as claimed in claim 1 the provision of a fuel collecting chamber between the second piston and-the means whereby the second piston delivers fuel to the motor, a by-pass for said chamber communicating with the fuel supply and with the outlet of the collecting chamber and including a freely sliding piston adapted to control the passage through the by-pass between the fuel supply and the outlet of the collecting chamber, means whereby the lubricant pressure acts on the freely sliding piston, and a regulator controlling the pressure of the lubricant including a diaphragm subjected at least on one side to air pressure, a set of levers operatively related at one end to said diaphragm, adjustable elastic means adapted to exert a constant pressure on the diaphragm inaddition to the air pressure, a slide valve subjected to the action of the lubricant presl sure and operatively related to the other end of said. set of levers, and means whereby the displacements of the slide valve control the passage of lubricant to the freely sliding piston whereby 5 the lubricant pressure and consequently the fuel pressure are determined by the air pressure acting on the diaphragm.

6. In a pump as claimed in claim 1, the provision of a rotary distributor, means for driving said distributor, means whereby the distributor is fed with fuel by the fuel delivery means and means whereby the distributor is lubricated by the lubricant from the pump cylinders at a pressure slightly above that of the fuel.

MOULET, JEAN LOUIS LEON ALEXANDRE ALBERT.

REFERENCES CITED The-followingreferences are of record in the file of this patent;

V UNITED STATES PATENTS Y Number 

